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Chip spotting

Some general rules of chip 'spotting', ie. determining, what the function of a chip or board of chips is.

Chips generally contain the following information:

XX - This a manufacturer and chip family specific code. You can look them up in this prefix listings.
44 - This is the chip family code (Look in the numerical listings.)
This is in indication of the fabrication process of the chip:
AC Advanced CMOS* (?)
FACT Fairchild Advanced CMOS* Technology (?)
F Fast
HC High speed CMOS*
HCT* High speed CMOS* TTL* compatible
LS* Low Power Scottky (=TTL*)
S Scottky (?) (=TTL*)
(Look on the TTL page for some background on these issues).
55 - Member code within the chip family
PP - Package code or whatever. This differs per manufacturer. (Look in the Postfixes listing).
1 - This is usually an indication of the speed of the device. It's generally also very manufacturer specific.
96 - The year of production
13 - The week of production
BB The production batch number within that week (Very rare)
The manufacturers logo
The country of manufacture (packaging)

If there are a lot of the same chips on a board, it usually is memory of one of two types:

If they are small chips (16..20 Pins, 7400-series like package):
Then it generally is dynamic RAM*. The numbers start with 41 or 82 and end with 64, 256, 1024 (or 1000?), 2048 (or 2000?). The last number is the number of Kbits in the package. If there is a 4 before this number: 464, 4256, 41000 The memory contains xx*4 Kbit.
If they are big chips (24+ Pins, EPROM-series size): Then it generally is static RAM*. But less of these chips are needed, because they are organized as xx*8 bits.
The code generally starts with 48 or 62 and ends with 64, 256, 1024. The latter is the number of Kbits. So a 64 contains 8k*8 bits.

If the chip has a ceramic window on it's top and is made of ceramic material instead of plastic, it generally is an EPROM* or a microcontroller combined with an EPROM*. The window of special UV-radiation transmitting light, can be used to clear the EPROM*, by UV-rays. These chips are generally covered with a sticker, which has two purposes: Stopping UV-rays from entering and telling what software the EPROM* contains. Generaly when a chip is made of ceramic material, it is an early production exemplar, which can become very hot, which would let a plastic package meld.

A ceramic package allows a window through which an UV-erasable chip can be reached. This type of package is also used for low-quantity production, rad-hard and hermetically sealed military packaging and sometimes because of the better thermal characteristics.

An email on this subject

On 20010529, Jeremy Ma wrote:
Please help me identify these two chips on a D2-438101-2 video board: ETCCY6BA0220ODD & ETCCY6BA0220EVN.  I think they are controlling the TV output format.

They are probably EPROM*'s. The first one (ending in ODD) contains the odd bytes of the program and the second one (ending in EVN) contains the even bytes of the program.

Are the numbers on stickers or printed directly on the chip? If on paper the chips are probably EPROM*'s otherwise they are ROM's or PROM*'s.

Are they DIP's having 24 to 32 pins? I would expect so.

The processor on the board probably has a 16 bits data bus (or more). Doesn't sound like a very modern board. When you follow the lines from the ROM's on the board you should be able to find the CPU*.

The program in the EPROM*'s controls the TV output format of course. But there may be a seperate small probably 8-pin EEPROM* in which the actual settings are kept when these program chips aren't flash EEPROM*'s.

More tips by Peter Faasse

At 00:40 13-08-01 -0800, Frederik Öhrn wrote:
It's a 68 pin quad* flatpack marked with the following:

9535 . W32060

A crude guess is that it's a microcontroller or some kind of programmable gate array chip.

Any clues on the origin and function of this chip would be very much appreciated.

A few small items w.r.t. 'chip-determination':

  1. look at the numbers (you did that...) The only part of it that i could make a sensible geuss at wou be the 9535; my guess would be that that is the production date.
  2. look at any logo's and/or (c) markings... (I've seen many a 80C31 that could only be traced down with (mentioned below..) trace-following and the (c) Intel text...
  3. count the pins (you did that too...); Make an educated guess what the chip would be doing from the context of where it's used: In your case: where's the chip coming from?
  4. determine analog/digital: a non-conclusive criterion would be the Vcc*: digital is mostly (for not so old systems) 5 Volts, analog is most other voltages.
  5. if digital:

If it's a CPU*, i'd gamble a 80196, but that's based only on the pin-count. As you see, there's a lot more that can be used to find out what's inside the chip than just the numbers you mentioned.....

Peter Faasse

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